Water Resources Allocation In The Naoli River Basin Under Different Future Climate Scenarios Based On The FLUS-WAS Model

As the global temperature increases and economic and social development continues,there has been an increase in human demand for water resources,intensifying the conflict between supply and demand of regional water resources.As one of the important grain production bases in China,the Naoli River Basin is important for ensuring food security in China,Due to the influence of both climate change and human activities,the hydrological processes in the Naoli river basin have changed significantly,with a decline in groundwater levels,breakdowns in the river,and a decrease in wetland areas.The future contradiction between water resources supply and demand with the background of climate change and national grain production increase plan will further intensify within the region.Therefore,To ensure the water security of the flexi river basin,the FLUS-WAS model of the Naoli river basin is constructed in this paper.in this paper,the FLUS-WAS model of the Naoli river basin is constructed with the Naoli river basin as the study area,and the Can ESM5climate model in CMIP6 is selected as the data driver to simulate and predict the future changes in land use,cross-sectional annual runoff and water resources in the study area.And based on the available water supply and water demand in the planning year(2035),the water allocation study was conducted under different scenarios.The specific results are as follows:(1)The database of hydrology and meteorology in the flexural river basin was constructed,and the FLUS and WAS models of the study area were constructed,and the models were tested for rate determination and applicability,and the results showed that:In the FLUS model,the Kappa coefficient validation result is greater than 0.75,and the simulation is good enough to be used for the simulation of future land use;The WAS model had NSE higher than 0.65 and correlation coefficients above 0.80 for all three hydrological stations in the hydrological cross section validation period;The relative error rate between the modeled multi-year average surface water resources and the actual surface water resources is 6.1%,and the relative error rates at 50%,75%and 90%frequency years respectively are 4.8%,5.7%and 5.6%;The total error of water allocation in the study area is 4.59%,and the model simulation is satisfactory and can be used for the evaluation and management of water resources in the study area.(2)Based on the constructed FLUS model,the simulation predicted the future land use in the Naoli river basin,and the results showed that:In 2026-2035,the areas of paddy land,dry land,forest land,transportation town residence site,grassland,water and unused land respectively are 6109.1,7560.21,6199.5,248.9,442.55,70.17 and 2533.57km~2;In 2036-2045,the areas of paddy land,dry land,forest land,transportation town residence site,grassland,water and unused land respectively are 7059.78,6885.95,6206.95,262.5,413.74,70.18 and 2264.91km~2.(3)Based on the future land use scenario and Can ESM5 mode data for CMIP6,the simulation predicted the amount of water resources in Naoli River Basin under different future climate scenarios,and the results showed that:Under the SSP1-2.6 scenario,the total annual average water resources are 35.63×10~8m~3 and 40.81×10~8m~3 respectively for 2026-2035 and 2036-2045 in the Naoli river basin;Under the SSP2-4.5 scenario,the total annual average water resources are 41.59×10~8m~3and 40.49×10~8m~3 respectively for 2026-2035 and 2036-2045 in the Naoli river basin;Under the SSP5-8.5 scenario,the total annual average water resources are 31.85×10~8m~3 and 43.44×10~8m~3respectively for 2026-2035 and 2036-2045 in the Naoli river basin;(4)Based on the socio-economic development of the Naoli river basin,the water allocation study for the planning year was carried out.The predicted water demand for the planning year is342,481.81×l0~4m~3.In scenariosⅠandⅢ,there is still a large water gap,and the proportion of groundwater exploitation is high.In scenariosⅡandⅣ,water supply is increased through the joint use of surface water and groundwater,and water resources basically reach a balance between supply and demand,surface water resources are exploited more,and the exploitation of groundwater is reduced.In terms of water use industry,urban living,rural living and industrial water use can generally be satisfied,but there is still a certain water use gap in agriculture.In terms of water consumption structure,the proportion of agricultural water consumption is extremely high in the Naoli river basin,so the total amount of agricultural water used can be controlled in the future by developing water-saving agriculture and optimizing the planting structure.The study results provide a reference basis for studying regional water resources research planning and management under future climate and land change scenarios.It also provides new ideas for the application of the WAS model to future climate scenarios.